Problems With Incredibly Noisy Renders In Cycles
Testing without materials attached may not be giving me the same results as you, but I have modified a couple of settings to generate this render:



I have increased your sun lighting somewhat and I added a spacey HDRI image as background, mostly so I could see what was going on inside the station. I then added a slight amount of clamping to direct and indirect. That render is at .10 and .05 respectively, I think. Smaller clamp amounts may have worked.... depends upon what you are going for.

HDRI from Blender Guru Pro Skies, not my work.

If this is moving in the direction you intend, I think some combination of clamping direct/indirect and working with the light paths -- https://www.blender.org/manual/render/cycles/optimizations/reducing_noise.html -- may get you where you want to go....

EDIT=====================

Sorry. I deleted your original file, so I downloaded again and made changes only to sun power settings and clamping to produce this:



I did not pack the space HDRI into the new blend file, as I believe it is copyright by Andrew Price in his Pro Skies.... so the second render was made without an HDRI in place.  Here's the modified file:



And just FYI: https://www.blendernation.com/2017/01/21/creating-looping-corridor/